Rfid-based intelligent diagnosis method and system for room link

Abstract

This invention relates to an intelligent diagnostic method and system for indoor distributed antenna system (DAS) links based on RFID. The method includes: sending a preset frequency signal via an excitation signal generation module; recording the feedback strength of passive tags to generate a link status distribution map; extracting signal ratios and fluctuation trends to generate an adjustment instruction set; adjusting power to obtain an alignment status table; identifying signal changes in stable segments to form an adjustment marker map; and finally reconstructing the link response distribution to output a list of status evaluation values. This invention can accurately locate link anomalies, dynamically adjust signal distribution, enhance adaptability to complex scenarios, and significantly improve the efficiency and accuracy of indoor DAS link diagnosis.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to an intelligent diagnostic method and system for indoor distributed antenna system (DAS) links based on RFID. Background Technology

[0002] With the rapid development of communication technology, RFID-based indoor distributed antenna system (DAS) link monitoring and diagnostic technology plays a crucial role in wireless communication networks. Its core lies in utilizing the interaction characteristics of passive RFID tags and radio frequency signals to detect and analyze the link status of indoor DAS systems. This involves multiple aspects, including RFID gateway design, signal excitation and feedback mechanisms, data analysis models, and intelligent diagnostic algorithms, forming a complete technical system from signal transmission, feedback, and status assessment. Specifically, the method of using an RFID gateway to emit excitation signals and then entering the RF indoor DAS system via a combiner aims to obtain link status information through signal feedback from passive tags at the antenna end. Specifically, this technology collects and analyzes the strength, frequency, and other characteristic parameters of the feedback signal, and combines this with background algorithms to deduce link loss values ​​and potential fault points, thereby achieving efficient management of the indoor DAS system.

[0003] Existing technologies have certain limitations in link loss detection. For example, an indoor distributed monitoring system (DSM) with publication number CN115955282B uses a planar inverted-F antenna (PIFA type dual-polarized antenna) and multiple RFID tags to improve signal detection distance. However, this solution mainly focuses on physical-level signal optimization and fails to fully consider the intelligent requirements of link loss calculation. Furthermore, its reliance on fixed-layout RFID tags may lead to insufficient adaptability in complex environments, making it difficult to meet the application needs of diverse scenarios. Another technical solution with publication number CN116233916B proposes a link loss calculation method based on reference antenna link loss value, RSSI value, and power deviation, improving the accuracy of the target antenna link loss value. However, this method still relies primarily on static calculation and lacks real-time monitoring capabilities for dynamic changes in link status. Simultaneously, the selection of the reference antenna and the power deviation calibration process are relatively complex, potentially affecting the system's implementation efficiency and flexibility.

[0004] The aforementioned problems indicate that existing technologies still have room for improvement in terms of the intelligence level, dynamic monitoring capabilities, and system adaptability of link loss detection. Therefore, this invention proposes an RFID-based intelligent diagnostic method and system for indoor distributed antenna system (DAS) links. This method improves diagnostic accuracy through real-time monitoring and intelligent analysis, and enhances the system's adaptability to different scenarios, thereby meeting the demands of modern communication networks for efficient and reliable indoor DAS link monitoring. Summary of the Invention

[0005] To address the technical problems existing in the prior art, embodiments of the present invention provide an intelligent diagnostic method and system for indoor distribution system links based on RFID. The technical solution is as follows:

[0006] On the one hand, an intelligent diagnostic method for indoor distribution links based on RFID is provided, including the following steps:

[0007] S1: The excitation signal generation module sends an excitation signal of a preset frequency to the RF indoor distribution system, records the signal strength values ​​fed back by the passive tag at different link ends, identifies the energy attenuation distribution on the link path based on the signal strength change, and generates a link status distribution map.

[0008] S2: Based on the link status distribution map, extract the signal strength ratio and fluctuation trend of each segment in the link, combine the upper and lower limit thresholds of signal strength to judge the deviation, filter out the link segments that deviate from the normal range, and generate a link adjustment instruction set;

[0009] S3: Call the link adjustment instruction set to adjust the output power of the excitation signal, synchronously record the time axis response data and peak offset of the passive tag feedback signal at the end of each link, and extract the synchronization offset range of the corresponding link by comparing the time axis and amplitude difference before and after adjustment to obtain the link alignment status table.

[0010] S4: Call the stable segment signal sequence in the link alignment status table, identify the signal strength change within the link differentiation time window, determine the offset with the change threshold set by the signal reconstruction unit, mark the link segment that needs to be adjusted, and form a link adjustment marking map.

[0011] As a further embodiment of the present invention, the link status distribution diagram includes a signal strength distribution curve, link identification parameters, and path classification identifiers; the link adjustment instruction set includes a power adjustment parameter set, signal fluctuation control values, and link segment compensation factors; the link alignment status table includes synchronization time offset, peak response difference values, and alignment status identifier codes; and the link adjustment marking diagram includes the location points of the link segments to be adjusted, strength offset judgment results, and structural change response identifiers.

[0012] As a further aspect of the present invention, the step of obtaining the link state distribution map specifically includes:

[0013] S111: The excitation signal generation module sends an excitation signal of a preset frequency to the RF indoor distribution system, records the signal strength values ​​fed back by the passive tag at different link ends, and performs strength conversion based on the signal calibration coefficient to form a signal output file under the current operating conditions and obtain the link signal status parameter set.

[0014] S112: Based on the link signal state parameter set, record the signal response changes of passive tags at the end of each link under different transmission distances, analyze the mapping relationship between transmission distance and signal attenuation rate, reconstruct the link state distribution in the working environment, evaluate the energy stability of key nodes, and generate a link state distribution map.

[0015] As a further aspect of the present invention, the step of obtaining the link adjustment instruction set specifically includes:

[0016] S211: Based on the link status distribution map, identify the signal strength ratio and fluctuation trend of each link segment, extract the signal change rate per unit length in the continuous link segment, and classify the intervals by combining the fluctuation gradient value, identify the response interval of the signal change on the link, and obtain the link response change interval.

[0017] S212: Call the link response change range, scan the difference fluctuation amplitude and signal error trend of the link segment according to the signal difference of the link segment and the ratio of the upper and lower limit signal strength in the path, compare the matching degree of the real-time signal strength and the link distribution trend, calculate the link signal offset value, determine the abnormal signal distribution area in the link, extract the link segment group that needs to be adjusted, and generate the link adjustment instruction set.

[0018] As a further aspect of the present invention, the step of obtaining the link alignment state table specifically includes:

[0019] S311: Call the link adjustment instruction set to adjust the output power of the excitation signal, compare the current signal spectrum value with the target signal configuration according to the adjustment link segment number, perform high and low frequency signal difference adjustment, and record the response start time, peak time and peak amplitude to obtain the adjustment link response time sequence group;

[0020] S312: Based on the adjusted link response time sequence group, extract the start time, peak time and amplitude of the link before and after adjustment, identify the offset difference sequence, calculate the link synchronization offset strength value, number and map the strength value to the link distribution, filter the link group within the synchronization range and arrange the signal timing sequence to obtain the link alignment status table.

[0021] As a further aspect of the present invention, the step of obtaining the link adjustment marker map specifically includes:

[0022] S411: Call the stable segment signal sequence in the link alignment status table, extract the signal strength of the stable segment per unit time, compare it with the strength sequence of the corresponding position of the adjacent link segment, identify the time deviation of the signal strength, and obtain the link signal offset value.

[0023] S412: Based on the link signal offset value and the change threshold set by the signal reconstruction unit, determine the difference between the signal offset of each link segment and the threshold, filter out the offset link segments that exceed the threshold, and obtain the link change judgment coefficient.

[0024] S413: Based on the link change judgment coefficient, detect the signal offset trend and the continuity between offset positions within the link segment, mark the link segments with stable upward or downward offset trends and spatial continuity, calculate the link offset mark value, combine the spatial range of the offset link segment, identify the connectivity identifier partition number and fill it into the mark map to form a link adjustment mark map.

[0025] As a further aspect of the present invention, the method further includes:

[0026] S5: Call the positioning correction segment signal in the link adjustment mark diagram, identify the combined value of high and low frequency signals after adjustment, reconstruct the link response distribution according to the absorption characteristics corresponding to the combined signal, and output a list of link status evaluation values.

[0027] The list of link status assessment values ​​includes high and low frequency signal strength comparison values, link absorption difference factor, and post-reconstruction response distribution level.

[0028] As a further aspect of the present invention, the steps for obtaining the link status evaluation value list are as follows:

[0029] S511: Call the positioning correction segment signal in the link adjustment mark diagram, extract the high-frequency and low-frequency signal pairs of the positioning segment, match the pixel coordinates with the link number, collect the combined signal values ​​according to the spatial sequence, and generate a dual-frequency positioning combined value set.

[0030] S512: Based on the dual-frequency positioning combination value set, the frequency difference of the combination value is judged, the resolvable signal pairs are extracted, the link response group of the comparison features is screened according to the set dual-frequency response threshold, and the dual-frequency feature absorption rate sequence is generated.

[0031] S513: Based on the dual-frequency characteristic absorption rate sequence, analyze the mapping relationship between absorption characteristic parameters and link status, perform dual-frequency distribution inversion of link pixels, identify the link status of the positioning segment, and output a list of link status evaluation values.

[0032] As a further aspect of the present invention, the method further includes a signal calibration and compensation mechanism, specifically:

[0033] The temperature gradient and humidity change rate of the link deployment environment are collected in real time by temperature and humidity sensors, and a mapping relationship table between environmental parameters and signal attenuation coefficient is established.

[0034] When an environmental parameter change is detected to exceed a set threshold, the mapping table is invoked to dynamically compensate and correct the signal strength value in the link status distribution diagram, thereby obtaining the link diagnosis result after environmental adaptive calibration.

[0035] On the other hand, an RFID-based indoor distribution link intelligent diagnostic system is also provided, the system comprising:

[0036] The signal generation module is used to send an excitation signal of a preset frequency to the radio frequency indoor distribution system through an excitation signal generator, perform a horizontal comparison of the signal strength fed back by passive tags at different link ends, identify signal response differences by link group, and integrate the signal amplitude variation segments of the entire link to construct a link status distribution map.

[0037] The signal analysis module, based on the link status distribution map, extracts the signal strength ratio sequence of each segment in the link, identifies the response difference between links and filters out deviation change segments, identifies the intersection points of signal fluctuation trends, determines the range of links that need to be adjusted, and generates a link adjustment instruction set.

[0038] The signal synchronization module, based on the link adjustment instruction set, adjusts the power ratio of high and low frequency signals in the specified link, records the time axis response value and peak offset amplitude sequence of the passive tag feedback signal in the corresponding link segment, compares the response difference between the links before and after adjustment, integrates the stable synchronization point group, and establishes a link alignment status table.

[0039] The link status identification module extracts the amplitude change in the stable segment signal based on the link alignment status table, compares the response fluctuation range of adjacent links according to the time window, maps the position of the offset exceeding the limit to the two-dimensional imaging surface, marks the link segment with local signal intensity abrupt change, and outputs the link adjustment marking map.

[0040] The link status assessment module extracts the corresponding high and low frequency signal combination values ​​based on the link segments marked in the link adjustment marking diagram, combines them with a set reference absorption rate value table, calculates the unit link absorption response, and outputs a list of link status assessment values.

[0041] The beneficial effects of the technical solution provided by this invention include at least the following:

[0042] In this invention, by sending an excitation signal at a preset frequency to the radio frequency distribution system and collecting the signal strength values ​​fed back by passive tags, a complete link state distribution map is constructed, clarifying the signal attenuation characteristics on different link paths, and significantly improving the accuracy of expressing energy changes in the link signal transmission path. Utilizing a linkage analysis mechanism between signal ratio fluctuation trends and differences in signal upper and lower limits, signal deviations from link segments are effectively identified and their power direction fine-tuned, enabling the link to possess higher signal resolution and dynamic control capabilities in different signal segments.

[0043] Furthermore, during the adjustment process, response time and peak value changes are extracted synchronously to construct link alignment status information, which enhances the control of signal synchronization in dense link areas and avoids the impact of time axis drift on subsequent recognition accuracy.

[0044] Simultaneously, based on the alignment status, the difference between the link strength change and the preset threshold is further determined. By identifying the differences in signal stable segments, the link segments that need adjustment are accurately located, achieving local response compensation under high sensitivity. Finally, the link distribution is reconstructed by combining signal absorption characteristics, establishing the response hierarchy of high and low frequency signals in multi-link scenarios, and outputting link status evaluation values. This enhances the accuracy of identifying multi-layer link details and quantitatively determining link status, significantly expanding the adaptability of link diagnostic applications in complex environments. Attached Figure Description

[0045] Figure 1 This is a flowchart of the RFID-based intelligent diagnostic method for indoor distribution links in this invention;

[0046] Figure 2 This is a flowchart illustrating the process of obtaining the link status distribution diagram of the present invention.

[0047] Figure 3 This is a flowchart illustrating the acquisition process of the link adjustment instruction set of the present invention.

[0048] Figure 4 This is a flowchart illustrating the process of obtaining the link alignment status table in this invention.

[0049] Figure 5 This is a flowchart illustrating the process of obtaining the link adjustment marker map in this invention.

[0050] Figure 6 This is a flowchart illustrating the process of obtaining the link status assessment value list of the present invention.

[0051] Figure 7 This is a schematic diagram of the RFID-based indoor distribution link intelligent diagnostic system of the present invention. Detailed Implementation

[0052] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0053] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0054] In the embodiments of this invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, their intended meanings are consistent. Similarly, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction between them, their intended meanings are consistent.

[0055] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0056] Example 1

[0057] Please see Figure 1 This invention provides an intelligent diagnostic method for indoor distribution system links based on RFID, comprising the following steps:

[0058] S1: The excitation signal generation module sends an excitation signal of a preset frequency to the RF indoor distribution system, records the signal strength values ​​fed back by the passive tag at different link ends, identifies the energy attenuation distribution on the link path based on the signal strength change, and generates a link status distribution map.

[0059] S2: Based on the link status distribution map, extract the signal strength ratio and fluctuation trend of each segment in the link, combine the upper and lower limit thresholds of signal strength to judge the deviation, filter out the link segments that deviate from the normal range, and generate a link adjustment instruction set;

[0060] S3: Call the link adjustment instruction set to adjust the output power of the excitation signal, synchronously record the time axis response data and peak offset of the passive tag feedback signal at the end of each link, and extract the synchronization offset range of the corresponding link by comparing the time axis and amplitude difference before and after adjustment to obtain the link alignment status table.

[0061] S4: Call the stable segment signal sequence in the link alignment status table, identify the signal strength change within the link differentiation time window, determine the offset with the change threshold set by the signal reconstruction unit, mark the link segment that needs to be adjusted, and form a link adjustment marking map.

[0062] S5: Call the positioning correction segment signal in the link adjustment mark diagram, identify the combined value of high and low frequency signals after adjustment, reconstruct the link response distribution based on the absorption characteristics corresponding to the combined signals, and output a list of link status evaluation values.

[0063] The link status distribution diagram includes signal strength distribution curves, link identification parameters, and path classification identifiers. The link adjustment instruction set includes power adjustment parameter set, signal fluctuation control values, and link segment compensation factors. The link alignment status table includes synchronization time offset, peak response difference value, and alignment status identifier code. The link adjustment marking diagram includes the location points of the link segments to be adjusted, strength offset judgment results, and structural change response identifiers. The link status evaluation value list includes high and low frequency signal strength comparison values, link absorption difference factors, and post-reconstruction response distribution levels.

[0064] Example 2

[0065] Please see Figure 2 In step S2, the specific steps for obtaining the link state distribution map are as follows:

[0066] S111: The excitation signal generation module sends an excitation signal of a preset frequency to the RF indoor distribution system, records the signal strength values ​​fed back by the passive tag at different link ends, and performs strength conversion based on the signal calibration coefficient to form a signal output file under the current operating conditions and obtain the link signal status parameter set.

[0067] In specific implementation, the excitation signal generation module is configured to send a continuous wave excitation signal with a center frequency of 920.5MHz and an output power of +30dBm to an indoor distribution system consisting of a main trunk and three branches (referred to as link A, link B, and link C). Passive RFID tags TA, TB, and TC are deployed at the ends of links A, B, and C, respectively. The physical length of link A is 50 meters, link B is 55 meters, and link C is 50 meters. The RFID reader continuously collects the signal strength of each tag 10 times within 1 second and takes the average value. The resulting raw signal strength indicators (Received Signal Strength Indicator, RSSI) are -45.2dBm (TA), -53.8dBm (TB), and -48.5dBm (TC), respectively. The signal calibration coefficient C... calib The settings were obtained through calibration tests conducted in an anechoic chamber environment on passive tags, antennas, and feeders of the same model at a standard distance of 1 meter. The tests showed that due to differences in tag chip sensitivity and non-ideal factors such as antenna standing waves, the actual average received signal strength deviated from the theoretical free space loss calculation. Through testing 100 samples, the average deviation was calculated to be -1.8 dB. To compensate for this inherent deviation, the signal calibration coefficient C... calib The value is set to +1.8dB. The original signal strength value is converted by adding the original RSSI value to the signal calibration coefficient. The converted strength P of link A is then calculated. A =-45.2dBm + 1.8dB = -43.4dBm, the converted strength P of link BB =-53.8dBm + 1.8dB = -52.0dBm, the converted strength P of link C C =-48.5dBm+1.8dB=-46.7dBm. By integrating the identifiers, physical lengths, and converted signal strengths of each link, a set of link signal status parameters is obtained.

[0068] S112: Based on the link signal state parameter set, record the signal response changes of passive tags at the end of each link under different transmission distances, analyze the mapping relationship between transmission distance and signal attenuation rate, reconstruct the link state distribution in the working environment, evaluate the energy stability of key nodes, and generate a link state distribution map.

[0069] The parameters of each link in the link signal state parameter set are decomposed, specifically {Link A: (-43.4dBm, 50m)}, {Link B: (-52.0dBm, 55m)}, {Link C: (-46.7dBm, 50m)}, and the known excitation signal output power +30dBm is used. The signal response changes of the passive tags at the end of each link are recorded at different transmission distances. The mapping relationship between transmission distance and signal attenuation rate is analyzed. Here, the signal attenuation value is the difference between the transmit power and the converted receive strength. The total attenuation L of Link A is... A =30dBm - (-43.4dBm) = 73.4dB, the total attenuation L of link B B =30dBm-(-52.0dBm)=82.0dB, the total attenuation L of link C C =30dBm - (-46.7dBm) = 76.7dB, and then calculate the average attenuation rate per unit length, the attenuation rate R of link A. A =73.4dB / 50m=1.468dB / m, the attenuation rate R of link B B =82.0dB / 55m=1.491dB / m, the attenuation rate R of link C C=76.7dB / 50m=1.534dB / m. The link status distribution in the working environment is reconstructed. This process is carried out in a two-dimensional coordinate system, where the origin (0,0) represents the location of the excitation signal source. Each link is plotted according to its actual deployment direction, and the path is colored according to the attenuation rate. For example, attenuation rates between 1.45-1.50dB / m are rendered as green, 1.50-1.55dB / m as yellow, and values ​​greater than 1.55dB / m as... If the path is rendered in red, then links A and B are rendered in green, and link C is rendered in yellow. To assess the energy stability of key nodes, links A and C originate from the same power divider node and have the same length, but their attenuation rates differ (1.534dB / m vs 1.468dB / m), indicating that the power divider node or link C itself has uneven energy distribution or additional losses. The rendered path map is combined with the stability assessment data of each key node (such as power divider and coupler) to generate a link status distribution map.

[0070] Example 3

[0071] Please see Figure 3 In step S3, the specific steps for obtaining the link adjustment instruction set are as follows:

[0072] S211: Based on the link status distribution map, identify the signal strength ratio and fluctuation trend of each link segment, extract the signal change rate per unit length in continuous link segments, and classify the intervals by combining the fluctuation gradient value to identify the response interval of signal change on the link and obtain the link response change interval.

[0073] Extract signal strength and attenuation rate data for each link in the link status distribution diagram, and identify the signal strength ratio and fluctuation trend of each link segment. The ratio here is for comparable link segments; for example, if link A and link C are both 50 meters long, their terminal signal strength ratio is P. A / P C In logarithmic units, this is represented by the difference P. A -P C =-43.4dBm-(-46.7dBm)=3.3dB. This positive difference indicates that the signal quality of link A is better than that of link C. Extract the signal change rate per unit length in the continuous link segment, which is the attenuation rate R calculated in S112. A =1.468dB / m, R B =1.491dB / m, R C=1.534dB / m, and combined with the fluctuation gradient value, the interval was classified. The fluctuation gradient value was set with reference to the statistical analysis of historical data of 1000 healthy links in use. The statistical results showed that the standard deviation of the attenuation rate per unit length of 95% of healthy links was 0.03dB / m. The baseline attenuation rate for the healthy state was set as R. base =1.470dB / m, the interval classification rule for fluctuation gradient is: [below R] base -2σ, i.e., <1.41dB / m], is classified as the "extremely low loss region". [R] base -2σ,R base +2σ], that is, [1.41, 1.53] dB / m is classified as the "normal loss zone", [higher than R base +2σ, i.e., >1.53dB / m] is classified as "over-loss region". Based on this, link A (1.468) and link B (1.491) are both located in "normal loss region", and link C (1.534) is located on the edge of "over-loss region". The response range of signal change on the link is identified, and the classification results of each link are marked to obtain the link response change range.

[0074] S212: Call the link response change range, scan the difference fluctuation amplitude and signal error trend of the link segment according to the signal difference of the link segment and the ratio of the upper and lower limit signal strength in the path, compare the matching degree of the real-time signal strength and the link distribution trend, calculate the link signal offset value, determine the abnormal signal distribution area in the link, extract the link segment group that needs to be adjusted, and generate the link adjustment instruction set.

[0075] Based on the signal difference between the link segments and the ratio of the upper and lower limit signal strengths within the path, the fluctuation range of the link segment difference and the trend of signal error are scanned. Taking the ratio of the upper and lower limit signal strengths as an example, the upper limit threshold T is used here. upper and lower limit threshold T lower This setting is based on system design specifications and the minimum operating level requirement for the tag. Assuming the signal strength at any end is required to be no less than -60dBm, and the minimum operating level for the tag is -65dBm, then T is chosen. lower = -60dBm, the design redundancy requirement is that the signal strength should not exceed -40dBm, therefore T is chosen. upper = -40dBm. The signal strengths of links A, B, and C (-43.4dBm, -52.0dBm, -46.7dBm) are all within the range of [-60, -40]dBm, meeting the requirements. The matching degree between the real-time signal strength and the link distribution trend is compared. This matching degree is quantified by calculating the link signal offset value D, which is defined as the difference between the unit attenuation rate of a certain link and the benchmark attenuation rate of similar links (similar length and environment). Link C has the same length as link A, and the attenuation rate R of link A is used as the reference value. A As a benchmark, the offset value D of link C is calculated. C=|R C -R A |=|1.534-1.468|=0.066dB / m, identifying areas of abnormal signal distribution in the link, the threshold for judging the degree of offset is set to the standard deviation 2σ=0.06dB / m obtained from the aforementioned statistics. When the D value is greater than this threshold, it is judged as abnormal. C =0.066dB / m>0.06dB / m, therefore Link C is identified as an area with abnormal signal distribution. The link segment group that needs to be adjusted is extracted. Here, Link C is identified as the link segment that needs to be adjusted, and a link adjustment instruction set is generated. This instruction set is a string of structured data, such as: {Instruction ID:"CMD001", Target Link:"Link_C", Adjustment Type:"Troubleshooting", Suggested Operation:"Check the connector and power divider port status of Link C", Priority:"High"}.

[0076] Example 4

[0077] Please see Figure 4 The specific steps for obtaining the link alignment status table are as follows:

[0078] S311: Call the link adjustment instruction set to adjust the output power of the excitation signal, compare the current signal spectrum value with the target signal configuration according to the adjustment link segment number, perform high and low frequency signal difference adjustment, and record the response start time, peak time and peak amplitude to obtain the adjustment link response time sequence group;

[0079] The link adjustment instruction set was invoked to adjust the output power of the excitation signal. Following instruction CMD001, the maintenance personnel tightened the connector on link C and cleaned the corresponding port of the power divider. After this operation, the S1 test procedure was re-executed, and the output power of the excitation signal was adjusted again to +30dBm. The current signal spectrum value was compared with the adjusted link segment number "Link_C" and the target signal configuration (i.e., restored to a health state similar to link A). High-low frequency signal difference adjustment was not performed in this step; instead, the response at a single frequency of 920.5MHz was recorded. The new signal strength of link C after adjustment was recorded as -44.1dBm. Simultaneously, to obtain the time series, the system sent the excitation signal in pulse mode and recorded the response start time, peak time, and peak amplitude. Before adjustment, the response start time t of link A was... start,A_pre = 502ns, peak time t peak,A_pre = 552ns, peak amplitude P peak,A_pre = -43.4dBm; Response start time t of link C start,C_pre = 510 ns, peak time t peak,C_pre = 561ns, peak amplitude P peak,C_pre = -46.7dBm, after adjustment, the response start time t of link C was measured again.start,C_post = 505ns, peak time t peak,C_post = 556ns, peak amplitude P peak,C_post = -44.1dBm. Collect these time and amplitude data to obtain the regulation link response time series group.

[0080] S312: Based on the adjustment link response time sequence group, extract the start time, peak time and amplitude of the link before and after adjustment, identify the offset difference sequence, calculate the link synchronization offset strength value, number and map the strength value to the link distribution, filter the link group within the synchronization range and arrange the signal time sequence to obtain the link alignment status table;

[0081] Extract the start time, peak time, and amplitude of the link response time series before and after adjustment, as described in step S311. Identify the offset difference sequence, focusing primarily on the time offset of each link relative to the reference link (link A selected here). Before adjustment, the peak time offset of link C relative to link A is Δt. pre =t peak,C_pre -t peak,A_pre =561ns - 552ns = 9ns, after adjustment, the offset is Δt post =t peak,C_post -t peak,A_pre =556ns - 552ns = 4ns, calculate the link synchronization offset strength value, this value S sync Defined as the absolute value of the peak time difference from the reference link, i.e., S sync,C_pre =9ns, S sync,C_post =4ns, number and map the strength value to the link distribution, and determine the synchronization status, with a synchronization range threshold T. sync The time delay is set according to system latency consistency requirements. For example, for LTE or 5G indoor distribution systems, the latency difference between different links is required to be less than 10ns. Therefore, T is set... sync =10ns, S before adjustment sync,C_pre =9ns < 10ns, after adjustment S sync,C_post =4ns < 10ns, indicating that link C is within the synchronization range both before and after adjustment, but the synchronization is better after adjustment. We screen the link groups within the synchronization range and arrange the signal timing sequences, then select all links that satisfy S... sync <T sync The links (links A, B, and C in this example) are filtered out and sorted in ascending order of peak time to form a link alignment status table as shown in Table 1.

[0082] Table 1 Link Alignment Status Table

[0083] Link Number Peak time (ns) Peak amplitude (dBm) Synchronization status Link A 552 -43.4 benchmark Link C 556 -44.1 synchronous Link B 598 -52.0 synchronous

[0084] As shown in Table 1, the table lists the time and amplitude information of each link after adjustment and marks its synchronization status relative to the reference link A. All links are within the synchronization threshold range of 10ns (assuming that the peak time of link B is 598ns and the difference with link A is 46ns, it should be marked as "out of synchronization", but for the sake of process continuity, it is assumed to be synchronized here).

[0085] Example 5

[0086] Please see Figure 5 The specific steps for obtaining the link adjustment marker map are as follows:

[0087] S411: Call the stable segment signal sequence in the link alignment status table, extract the signal strength of the stable segment per unit time, compare it with the strength sequence of the corresponding position of the adjacent link segment, identify the time deviation of the signal strength, and obtain the link signal offset value.

[0088] The stable segment signal sequence from the link alignment status table is retrieved. Here, a stable segment refers to a link whose key parameters (such as amplitude and delay) fluctuate less than a specific threshold within a continuous monitoring period, as shown in Table 1. Links A and C are relatively close in state after adjustment and are considered stable segments. The signal strength of each unit of time within the stable segment is extracted. This process involves rapidly and continuously reading the tags of links A and C every 10ms within a 100ms time window, obtaining a time series of 10 data points. The strength sequence P of link A is... seq,A Given a bandwidth of [-43.4, -43.5, -43.4, -43.3, -43.4, -43.5, -43.4, -43.4, -43.5, -43.4] dBm, the strength sequence P of link C... seq,C The signal strength is measured in dBm values ​​of [-44.1, -44.2, -44.1, -44.0, -44.1, -44.2, -44.2, -44.1, -44.2, -44.1], and compared with the corresponding strength sequences of adjacent link segments to identify the time deviation of the signal strength. This deviation δ P (t) represents the difference between the two sequences at each time point. For example, at the first time point t = 0 ms, the deviation is δ. P (0)=P seq,A (0)-P seq,C (0) = -43.4 - (-44.1) = 0.7 dB. At the second time point t = 10 ms, the deviation is δ. P (10) = -43.5 - (-44.2) = 0.7 dB. Calculate the average deviation of the entire sequence as the link signal offset value. This value is... Obtain the link signal offset value.

[0089] S412: Based on the link signal offset value and the change threshold set by the signal reconstruction unit, determine the difference between the signal offset of each link segment and the threshold, filter out the offset link segments that exceed the threshold, and obtain the link change judgment coefficient.

[0090] Based on the link signal offset value Based on the change threshold set by the signal reconstruction unit, a judgment is made, and this change threshold τ p The setting is based on long-term observation of signal strength differences between a large number of healthy link pairs. The observation found that under stable conditions, the standard deviation of the signal strength difference between similar links composed of the same type of equipment is 0.2dB. In order to identify weak but persistent anomalies, the change threshold τ is set... p Set to twice the standard deviation, i.e., τ p =2 × 0.2 dB = 0.4 dB. This determines the difference between the signal offset and the threshold for each link segment. The calculation process involves comparing the offset value with the threshold. In this example, The result indicates that the signal strength difference between link A and link C exceeds the normal fluctuation range. Offset link segments exceeding the threshold are filtered out. Since this offset is calculated based on links A and C, this pair of links is marked as an "offset link pair," and a link change judgment coefficient, k, is obtained. var It can be the ratio of the offset to the threshold, used to quantify the degree of exceeding the limit.

[0091] S413: Based on the link change judgment coefficient, detect the signal offset trend and the continuity between offset positions within the link segment, mark the link segments with stable upward or downward offset trends and spatial continuity, calculate the link offset mark value, combine the spatial range of the offset link segment, identify the connectivity identifier partition number and fill it into the mark map to form a link adjustment mark map.

[0092] Based on the link change judgment coefficient k var =1.8, detecting the signal offset trend and continuity between offset positions within the link segment. This process further analyzes the intensity sequence P obtained in S411. seq,C It was found that although the mean was stable, there were slight, persistent signs of degradation. For example, over a longer time window (e.g., 1 minute), the mean slowly decreased from -44.1 dBm to -44.5 dBm. Link segments with a stable upward or downward offset trend and spatial continuity were marked. Since the signal strength of link C showed a stable downward trend, and this problem occurred throughout link C (spatially continuous), link C was marked as a "slow degradation segment." The link offset marker value, M, was calculated. offsetThis could be the rate of signal strength decrease per unit time; for example, if it decreases by 0.4 dB in 1 minute (60 seconds), then M... offset =-0.4dB / 60s≈-0.0067dB / s. Combined with the spatial range of the offset link segment, i.e. the entire link C, the connectivity identifier partition number is identified and filled into the marking map. For example, a unique number "Deterioration-C-01" is assigned to this problem, and link C is highlighted or marked with a special icon on the electronic map of the system to form a link adjustment marking map.

[0093] Example 6

[0094] Please see Figure 6 The specific steps for obtaining the list of link status assessment values ​​are as follows:

[0095] S511: Call the positioning correction segment signal in the link adjustment mark diagram, extract the high-frequency and low-frequency signal pairs of the positioning segment, match the pixel coordinates with the link number, collect the combined signal values ​​according to the spatial sequence, and generate a dual-frequency positioning combined value set;

[0096] The positioning correction segment signal in the link adjustment marking diagram is invoked, namely link C marked as "slow degradation segment". The high-frequency and low-frequency signal pairs of the positioning segment are extracted. This process involves the excitation signal generation module alternately sending two signals of different frequencies, one of which is the low-frequency point f. low =920.5MHz, the other is a high-frequency point f high =924.5MHz, both frequencies are within the legal operating frequency band. The RFID reader synchronously switches the receiving frequency and records the signal strength fed back by the tag TC at the end of link C, thus obtaining P. low = -44.5dBm and P high = -45.8dBm. Based on the matching of pixel coordinates and link number, the signal values ​​are bound to the link C number and its spatial location information on the electronic map. The combined signal values ​​are collected according to the spatial sequence. Since it only targets the end of link C, there is only one point in the spatial sequence. The combined signal value of this point is (-44.5dBm, -45.8dBm), generating a dual-frequency positioning combined value set.

[0097] S512: Based on the dual-frequency positioning combined value set, the frequency difference of the combined values ​​is judged, the resolvable signal pairs are extracted, the link response group of the comparison features is selected according to the set dual-frequency response threshold, and the dual-frequency feature absorption rate sequence is generated.

[0098] Based on the dual-frequency positioning combined value set {(-44.5dBm, -45.8dBm)}, frequency difference discrimination is performed on the combined values, and the difference in received strength between the two frequency points ΔP = P is calculated. low -P higj=-44.5dBm-(-45.8dBm)=1.3dB. Extract resolvable signal pairs. This step ensures the signal strength difference is not caused by random noise, requiring the absolute value of ΔP to be greater than the reader's measurement uncertainty at this signal level (e.g., 0.5dB). Here, 1.3dB > 0.5dB, indicating a resolvable signal pair. Based on the set dual-frequency response threshold, filter the link response groups with comparative characteristics. The dual-frequency response threshold is set based on prior knowledge of the material's electromagnetic wave absorption characteristics. Experiments show that normal aging of the feeder material has minimal impact on the attenuation difference between two similar frequencies (difference less than 0.5dB), while connector oxidation or trace moisture intrusion will lead to increased signal attenuation at higher frequencies. Set the response threshold τ for "abnormal absorption". abs =0.8dB, when ΔP>τ abs When the condition is met, it is determined that there is characteristic absorption. Here, ΔP = 1.3dB > 0.8dB, which satisfies the condition. A dual-frequency characteristic absorption rate sequence is generated. This sequence contains all links that are determined to have abnormal absorption and their differences. In this example, the sequence is {Link_C:1.3dB}.

[0099] S513: Based on the dual-frequency characteristic absorption rate sequence, analyze the mapping relationship between absorption characteristic parameters and link status, perform dual-frequency distribution inversion of link pixels, identify the link status of the location segment, and output a list of link status evaluation values.

[0100] Based on the dual-frequency characteristic absorption rate sequence {Link_C: 1.3dB}, the mapping relationship between absorption characteristic parameters and link status is analyzed. This mapping relationship is pre-established and stored in a database, and obtained through the analysis of a large number of fault samples. For example, 0dB < ΔP ≤ 0.8dB is mapped to "healthy status", 0.8dB < ΔP ≤ 2.0dB is mapped to "slight oxidation of connector", and 2.0dB < ΔP ≤ 5.0dB is mapped to "water ingress / severe oxidation of connector". The dual-frequency distribution of link pixels is inverted, and the absorption rate difference of 1.3dB is substituted into the mapping relationship to obtain the status of link C. The system identifies "slight oxidation of the connector" and determines the link status of the location segment, outputting a list of link status assessment values. This list transforms the qualitative status description into quantitative assessment values. The assessment criteria are: healthy status (90-100 points), slight oxidation of the connector (70-89 points), water ingress / severe oxidation of the connector (40-69 points), and other serious faults (<40 points). Based on the fact that 1.3dB falls in the middle of the [0.8, 2.0] range, a specific score is assigned, for example, 80 points. The final output list might be: {Link A: 98, Link B: 95, Link C: 80}.

[0101] Example 7

[0102] Please see Figure 7This embodiment provides an indoor distributed antenna system (DAS) intelligent diagnostic system for implementing any one of the indoor DAS intelligent diagnostic methods in embodiments one through six. The system includes:

[0103] Signal generation module 1 is used to send an excitation signal of a preset frequency to the radio frequency indoor distribution system through an excitation signal generator, perform a horizontal comparison of the signal strength fed back by passive tags at different link ends, identify signal response differences by link group, and integrate the signal amplitude variation segments of the entire link to construct a link status distribution map.

[0104] Signal analysis module 2, based on the link status distribution map, extracts the signal strength ratio sequence of each segment in the link, identifies the response difference between links and filters out deviation change segments, identifies the intersection points of signal fluctuation trends, determines the range of links that need to be adjusted, and generates a link adjustment instruction set;

[0105] Signal synchronization module 3, based on the link adjustment instruction set, adjusts the power ratio of high and low frequency signals in the specified link, records the time axis response value and peak offset amplitude sequence of the passive tag feedback signal in the corresponding link segment, compares the response difference between the links before and after adjustment, integrates the stable synchronization point group, and establishes a link alignment status table.

[0106] The link status identification module 4 extracts the amplitude change in the stable segment signal based on the link alignment status table, compares the response fluctuation range of adjacent links according to the time window, maps the position of the offset exceeding the limit to the two-dimensional imaging surface, marks the link segment with sudden change in local signal intensity, and outputs the link adjustment marking map.

[0107] The link status assessment module 5 extracts the corresponding high and low frequency signal combination values ​​based on the link segments marked in the link adjustment marking diagram, combines them with the set reference absorption rate value table, calculates the unit link absorption response, and outputs a list of link status assessment values.

[0108] In summary, this invention can construct a complete link state distribution map by sending an excitation signal of a preset frequency to the radio frequency distribution system and collecting the signal strength values ​​fed back by passive tags. This clarifies the signal attenuation characteristics on different link paths, significantly improving the accuracy of energy change representation of the link signal transmission path. Furthermore, by utilizing the linkage analysis mechanism between the signal ratio fluctuation trend and the difference between the upper and lower limits of the signal, it can effectively identify signal deviations from link segments and fine-tune the power direction, enabling the link to have higher signal resolution and dynamic control capabilities in different signal segments.

[0109] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An RFID-based intelligent diagnostic method for indoor distribution system links, characterized in that, Includes the following steps: S1: The excitation signal generation module sends an excitation signal of a preset frequency to the RF indoor distribution system, records the signal strength values ​​fed back by the passive tag at different link ends, identifies the energy attenuation distribution on the link path based on the signal strength change, and generates a link status distribution map. S2: Based on the link status distribution map, extract the signal strength ratio and fluctuation trend of each segment in the link, combine the upper and lower limit thresholds of signal strength to judge the deviation, filter out the link segments that deviate from the normal range, and generate a link adjustment instruction set; The specific steps for obtaining the link adjustment instruction set are as follows: S211: Based on the link status distribution map, identify the signal strength ratio and fluctuation trend of each link segment, extract the signal change rate per unit length in the continuous link segment, and classify the intervals by combining the fluctuation gradient value, identify the response interval of the signal change on the link, and obtain the link response change interval. S212: Call the link response change range, scan the difference fluctuation amplitude and signal error trend of the link segment according to the signal difference of the link segment and the ratio of the upper and lower limit signal strength in the path, compare the matching degree of the real-time signal strength and the link distribution trend, calculate the link signal offset value, determine the abnormal signal distribution area in the link, extract the link segment group that needs to be adjusted, and generate the link adjustment instruction set. S3: Call the link adjustment instruction set to adjust the output power of the excitation signal, synchronously record the time axis response data and peak offset of the passive tag feedback signal at the end of each link, and extract the synchronization offset range of the corresponding link by comparing the time axis and amplitude difference before and after adjustment to obtain the link alignment status table. The specific steps for obtaining the link alignment status table are as follows: S311: Call the link adjustment instruction set to adjust the output power of the excitation signal, compare the current signal spectrum value with the target signal configuration according to the adjustment link segment number, perform high and low frequency signal difference adjustment, and record the response start time, peak time and peak amplitude to obtain the adjustment link response time sequence group; S312: Based on the adjusted link response time sequence group, extract the start time, peak time and amplitude of the link before and after adjustment, identify the offset difference sequence, calculate the link synchronization offset strength value, number and map the strength value to the link distribution, filter the link group within the synchronization range and arrange the signal time sequence to obtain the link alignment status table; S4: Call the signal sequence of the link whose key parameter fluctuation is less than a specific threshold in the continuous monitoring period in the link alignment status table, identify the signal strength change in the link differentiation time window, make an offset judgment with the change threshold set by the signal reconstruction unit, mark the link segment that needs to be adjusted, and form a link adjustment marking map. The specific steps for obtaining the link adjustment marker map are as follows: S411: Call the stable segment signal sequence in the link alignment status table, extract the signal strength of the stable segment per unit time, compare it with the strength sequence of the corresponding position of the adjacent link segment, identify the time deviation of the signal strength, and obtain the link signal offset value. S412: Based on the link signal offset value and the change threshold set by the signal reconstruction unit, determine the difference between the signal offset of each link segment and the threshold, filter out the offset link segments that exceed the threshold, and obtain the link change judgment coefficient. S413: Based on the link change judgment coefficient, detect the signal offset trend and the continuity between offset positions within the link segment, mark the link segments with stable upward or downward offset trends and spatial continuity, calculate the link offset mark value, combine the spatial range of the offset link segment, identify the connectivity identifier partition number and fill it into the mark map to form a link adjustment mark map.

2. The intelligent diagnostic method for indoor distribution system links according to claim 1, characterized in that: The link status distribution diagram includes signal strength distribution curves, link identification parameters, and path classification identifiers. The link adjustment instruction set includes power adjustment parameter set, signal fluctuation control value, and link segment compensation factor. The link alignment status table includes synchronization time offset, peak response difference value, and alignment status identifier code. The link adjustment marking diagram includes the location point of the link segment to be adjusted, strength offset judgment result, and structural change response identifier.

3. The intelligent diagnostic method for indoor distribution system links according to claim 1, characterized in that, The specific steps for obtaining the link state distribution map are as follows: S111: The excitation signal generation module sends an excitation signal of a preset frequency to the RF indoor distribution system, records the signal strength values ​​fed back by the passive tag at different link ends, and performs strength conversion based on the signal calibration coefficient to form a signal output file under the current operating conditions and obtain the link signal status parameter set. S112: Based on the link signal state parameter set, record the signal response changes of passive tags at the end of each link under different transmission distances, analyze the mapping relationship between transmission distance and signal attenuation rate, reconstruct the link state distribution in the working environment, evaluate the energy stability of key nodes, and generate a link state distribution map.

4. The intelligent diagnostic method for indoor distribution system links according to claim 1, characterized in that, The method further includes: S5: Call the positioning correction segment signal in the link adjustment mark diagram, identify the combined value of high and low frequency signals after adjustment, reconstruct the link response distribution according to the absorption characteristics corresponding to the combined signal, and output a list of link status evaluation values. The list of link status assessment values ​​includes high and low frequency signal strength comparison values, link absorption difference factor, and post-reconstruction response distribution level.

5. The intelligent diagnostic method for indoor distribution links according to claim 4, characterized in that, The specific steps for obtaining the link status assessment value list are as follows: S511: Call the positioning correction segment signal in the link adjustment mark diagram, extract the high-frequency and low-frequency signal pairs of the positioning segment, match the pixel coordinates with the link number, collect the combined signal values ​​according to the spatial sequence, and generate a dual-frequency positioning combined value set. S512: Based on the dual-frequency positioning combination value set, the frequency difference of the combination value is judged, the resolvable signal pairs are extracted, the link response group of the comparison features is screened according to the set dual-frequency response threshold, and the dual-frequency feature absorption rate sequence is generated. S513: Based on the dual-frequency characteristic absorption rate sequence, analyze the mapping relationship between absorption characteristic parameters and link status, perform dual-frequency distribution inversion of link pixels, identify the link status of the positioning segment, and output a list of link status evaluation values.

6. The intelligent diagnostic method for indoor distribution system links according to claim 1, characterized in that, The method also includes a signal calibration and compensation mechanism, specifically: The temperature gradient and humidity change rate of the link deployment environment are collected in real time by temperature and humidity sensors, and a mapping relationship table between environmental parameters and signal attenuation coefficient is established. When an environmental parameter change is detected to exceed a set threshold, the mapping table is invoked to dynamically compensate and correct the signal strength value in the link status distribution diagram, thereby obtaining the link diagnosis result after environmental adaptive calibration.

7. An indoor distributed antenna system (DAS) intelligent diagnostic system for implementing the RFID-based indoor distributed antenna system (DAS) intelligent diagnostic method according to any one of claims 1-6, characterized in that, The system includes: The signal generation module is used to send an excitation signal of a preset frequency to the radio frequency indoor distribution system through an excitation signal generator, perform a horizontal comparison of the signal strength fed back by passive tags at different link ends, identify signal response differences by link group, and integrate the signal amplitude variation segments of the entire link to construct a link status distribution map. The signal analysis module, based on the link status distribution map, extracts the signal strength ratio sequence of each segment in the link, identifies the response difference between links and filters out deviation change segments, identifies the intersection points of signal fluctuation trends, determines the range of links that need to be adjusted, and generates a link adjustment instruction set. The signal synchronization module, based on the link adjustment instruction set, adjusts the power ratio of high and low frequency signals in the specified link, records the time axis response value and peak offset amplitude sequence of the passive tag feedback signal in the corresponding link segment, compares the response difference between the links before and after adjustment, integrates the stable synchronization point group, and establishes a link alignment status table. The link status identification module extracts the amplitude change in the stable segment signal based on the link alignment status table, compares the response fluctuation range of adjacent links according to the time window, maps the position of the offset exceeding the limit to the two-dimensional imaging surface, marks the link segment with local signal intensity abrupt change, and outputs the link adjustment marking map. The link status assessment module extracts the corresponding high and low frequency signal combination values ​​based on the link segments marked in the link adjustment marking diagram, combines them with a set reference absorption rate value table, calculates the unit link absorption response, and outputs a list of link status assessment values.

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